Higher fish consumption patterns are associated with beneficial gut microbiome profile and lower depressive symptoms in breast cancer survivors

Abstract: Gut microbial diversity and composition have been associated both physical and psychological health outcomes. Treatment for breast cancer can place breast cancer survivors (BCS) at risk for alterations in gut microbiome composition and depression. Current guidelines for BCS recommend increased fish consumption, however more work is necessary in understanding how fish and associated omega-3 fatty acid consumption impact gut health and depressive symptoms.

Objective: To evaluate the relationship between typical fish consumption and the outcomes of gut microbiome composition and depressive symptoms in BCS.

Methods: Typical fish consumption and depressive symptoms (CESD) were collected in BCS (n=98). Frequency of weekly fish consumption (assigned to 4 categories, < 1, 1, 2 or ≥ 3) and CESD (for depressive symptoms) were collected via self-report. Gut microbiome composition was quantified in a subset of the cohort (n=46). DNA extracted from stool was used to sequence the 16S rRNA gene. Exploratory data analysis was conducted with a focus on differences in microbial diversity and composition among BCS by level of fish consumption. A linear regression model was used to evaluate the association between fish frequency and gut microbial diversity and CESD total score.

Results: Fish consumption was significantly associated with alpha diversity (p=0.02, mean servings/week ( < 1/wk, 11.8±6; 1/wk 11.4±6.5; 2/wk 11.9±3.9; ≥3/wk 21.0±8.6). Bifidobacterium was significantly higher in BCS with reported fish consumption >1 serving per week (p=0.03). CESD total score was significantly lower in BCS with reported fish consumption >1 serving per week compared to < 1 serving/wk (p=0.04, < 1/wk 13.9±10.8; >1/wk 9.5±7.3).

Significance: Further education and outreach is necessary in BCS promoting increased fish consumption for better gut and psychological health. Future work is also necessary evaluating the role of omega-3 fatty acid, a bioactive component of fish, in gut microbiome composition in BCS and other populations.